Upper feed mechanism

ABSTRACT

A SEWING MACHINE HAVING AN UPPER FEED MECHANISM ADAPTED TO BE USED INDEPENDENT OF OR IN CONJUNCTION WITH A CONVENTIONAL LOWER FEED. THE UPPER FEED DOG IS GIVEN ADVANCE AND RETURN MOVEMENT THROUGH A QUADRATIC LINKAGE WHICH IS ROCKED BY A PAIR OF ROCKER ARMS DRIVEN THROUGH A REGULATING MEMBER FROM AN ECCENTRICALLY OSICLATED PITMAN. A TIMING BELT TRANSMITS MOTION FROM THE SHAFT TO A SHAFT ON WHICH THE PITMAN ECCENTRIC IS MOUNTED. THIS LATTER SHAFT ALSO MOUNTS A SECOND TIMING BELT WHICH DRIVES A SECOND ECCENTRIC TO GIVE LIFT AND DROPPING MOVEMENT TO THE UPPER FEED DOG. THE REGULATING MEMBER MAY BE ADJUSTED TO CHANGE THE UPPER FEED EITHER SIMULTANEOUSLY OR INDEPENDENTLY OF THE LOWER FEED MECHANISM BY EITHER OF TWO REGULATING SCREWS OPERATING THROUGH A PLURALTY FO CRANKS AND COUPLES MOUNTED ON A PAIR OF CONCENTRIC SHAFTS. A FOOT PEDAL OPERATED LINKAGE TURNS THE INNER OF THE TWO SHAFTS, INDEPENDENTLY OF THE TWO REGULATING SCREWS, TO EFFECT A QUICK CHANGE OF THE UPPER FEED ONLY FOR AS LONG AS THE PEDAL IS DEPRESSED, RETURNING THE UPPER FEED TO ITS PRESENT AMOUNT UPON RELEASE THEREOF. AN INDICATOR SCALE AND POINTED SHOW THE DIFFERENCE IN FEEDS BETWEEN BOTTOM AND TOP FEED DOGS AS SET BY THE REGULATING SCREW THAT CHANGES THE UPPER FEED ONLY.

p 20, 1971 E. M. WILLENBACHER ErAL 3,605,662

UPPER FEED MECHANISM Filed May 1, 1970 4 Sheets-Sheet 1 J 1 3 INVENTORS S8 El'lCh M. wlllenbocher, Korl- Heinz Michel and Werner J. Meyer WITNESS ATTO Sept- 1971 E. M. WILLENBACHER ETAL 3,605,662

UPPER FEED MECHANISM Filed May 1, 1970 4 Sheets-Sheet 2 ATT p 20, 1971 E. M. WILLENBACHER ETAL 3,605,662

UPPER FEED MECHANISM Filed May 1, 1970 4 Sheets-Sheet 5 INVENTORS Erich M. Willepbocher, BY KOfl-HGIHZ Mlchel and Werner J. Mo er WITNESS d flaw JW-EWW M gi P 20, 1971 E. M. WILLENBACHER EI'AL 3,605,662

UPPER FEED MECHANISM Filed May 1, 1970 4 Sheets-Sheet 4.

INVENTORS Erlch M. Willeqbacher, BY Korl-Helnz MIChGI and Werner J. MCI er wrmzss W d -v yantf xung Zi mm AT 0 RNEY United States Patent 0 3,605,662 UPPER FEED MECHANISM Erich M. Willenbacher and Karl-Heinz Michel, Karlsruhe- Hagsfeld, and Werner J. Mayer, Karlsruhe-Durlach,

Germany, assignors to The Singer Company, New

York, N.Y.

Filed May 1, H70, Ser. No. 33,751 Int. Cl. DtlSb 27/04 US. Cl. 112-212 19 Claims ABSTRACT OF THE DISCLOSURE A sewing machine having an upper feed mechanism adapted to be used independent of or in conjunction with a conventional lower feed. The upper feed dog is given advance and return movement through a quadratic linkage which is rocked by a pair of rocker arms driven through a regulating member from an eccentrically oscillated pitman. A timing belt transmits motion from the shaft to a shaft on which the pitman eccentric is mounted. This latter shaft also mounts a second timing belt which drives a second eccentric to give lift and dropping movement to the upper feed dog. The regulating member may be adjusted to change the upper feed either simultaneously or independently of the lower feed mechanism by either of two regulating screws operating through a plurality of cranks and couples mounted on a pair of concentric shafts. A foot pedal operated linkage turns the inner of the two shafts, independently of the two regulating screws, to effect a quick change of the. upper feed only for as long as the pedal is depressed, returning the upper feed to its present amount upon release thereof. An indicator scale and pointer show the difference in feeds between bottom and top feed dogs as set by the regulating screw that changes the upper feed only.

BACKGROUND OF THE INVENTION This invention relates to sewing machines and more particularly to an upper work feeding mechanism therefor having a work feeding foot adapted to operate on the top ply of material being sewn to advance the material past the stitch forming instrumentalities and which may be adapted to operate in conjunction with a conventional bottom feed mechanism operating on the bottom ply of the Work.

In order to obtain a uniform work feeding action, so as to prevent gathering or stretching of one ply of work relative to the others, it is known in industrial type sewing machines which operate on two or more plies of fabric, to impart a feeding movement to both the top and bottom work surfaces by means of two separate feeding members. These members, known in the art as feed dogs, preferably include a plurality of teeth which act upon the surface of the work when the needle is Withdrawn therefrom to feed the work in the preferred direction to and from the stitching point. Because the presser foot under some conditions exerts a retarding force on the top ply, and because when sewing plies of different materials together there may be a different feeding rate applied to the different materials by the feed dogs acting thereon, it is desirable. to adjust the feed of the top and bottom feed dogs independently to obtain the same feed on all the plies. This is also necessary when it is desired to obtain a gathering or stretching of one ply relative to the others. Furthermore, once the relative feed rates for the top and bottom feed dogs are properly adjusted and a change in stitch length of the entire work is required it is desirable to simultaneously adjust both the top and bottom feeds without changing the relative feeds so that there is a minimum of time lost in chang- "ice ing the sitch length. Moreover, during certain operations, such as during straight stitch sewing without a stretching or gathering action, it may be necessary to elfect a variation, such as a gathering, during a small portion of the cycle. For this urpose it is of course desirable to effect such an operation without changing the previous setting of the feed dogs and to be able to come back to the normal conditions rapidly and without any readjustments. These desirable features are geared to a high speed sewing operation which must not be sacrificed for the sake of simplicity in control. The prior art has not provided the high speed capability in a sewing machine having an upper feed mechanism, and especially in such a machine having the aforesaid control features in combination with an upper feed.

SUMMARY OF THE INVENTION It is, therefore, a primary object of this invention to provide in a sewing machine an improved upper feed mechanism adapted for high speed operation, and which may be used in conjunction with a conventional lower feed.

A further object of this invention is to provide, in a sewing machine having a lower feed dog, an improved upper feed mechanism which may be adjusted simultaneously with the lower feed dog to regulate the stitch length being sewn.

A still further object of this invention is to provide, in a sewing machine having a lower feed dog, an improved upper feed mechanism which can be adjusted independently of said lower feed to change the rate of feed of the top work plies without effecting the feed of the lower work plies, and which can also be adjusted to change the lower feed mechanism together with the upper feed.

A yet still further object of this invention is to provide in a sewing machine an upper feed mechanism for use in conjunction with a lower feed mechanism which is compact and may be installed on existing lower feed sewing machines.

Another object of the present invention is to provide in a sewing machine having a lower feed, an upper feed mechanism having means for rapidly effecting a difference between the upper and lower feed rates and returning the feed rates to the previous condition.

These and other objects are achieved by providing, preferably in a sewing machine having a conventional lower feed mechanism, an upper feed mechanism comprising a quadratic linkage supported upper feed dog which is given feed advance and return motion by an eccentric drive element which operatively is connected to the arm shaft of the machine and is also operatively connected to the quadratic linkage by rocker arm means. For quiet high speed operation the eccentric drive element is driven by a belt from the arm shaft. A toggle type regulating mechanism, interposed between the eccentric drive element and the rocker arm means, is operatively connected to a first control shaft whose angular setting is elfected by a manually adjustable regulator screw operatively coupled to a shifting lever mounted on the first control shaft to change independently the upper feed advance and return motion, and hence the upper feed relative to that of the lower feed. A second control shaft, which is operatively coupled to the first control shaft to turn the same, is angularly effected by a second manually adjustable regulating screw which is further interconnected to the lower feed mechanism so that when the second regulating screw is turned both the upper and lower feed dog motions are simultaneously effected. To effect a rapid difference between the upper and lower feeds and for returning the feeds to their prior settings there is provided a foot pedal operatively connected to a crank on the first control shaft. When the pedal is depressed the first control shaft is temporarily disengaged from the regulating screws and is turned to effect the upper feed relative to the lower feed. When the pedal is released the first shaft returns to its initial position as determined by the two regulating screws. Lift and fall motion of the upper feed dog is obtained by an eccentric operatively driven from the arm shaft and is operatively connected to the feed dog. This eccentric is also driven by a belt operatively connected to the arm shaft and acts against a bellcrank to give lift to the feed dog while a spring biases the bellcrank to provide the dropping action of the feed dog.

BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the nature and objects of this invention reference should be had to the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a rear perspective view of a position of a sewing machine incorporating the preferred embodiment of the upper feed mechanism of the present invention with portions thereof broken away, cross sectioned and shown in phantom to clearly show the mechanism;

FIG. 2 is an end perspective view of a portion of the sewing machine illustrated in FIG. 1 with portions thereof broken away, cross sectioned and shown in phantom;

FIG. 3 is an elevational view of a portion of the feed advance and return mechanism of the present invention with parts thereof removed and portions thereof cross sectioned to illustrate clearly the feed linkages;

FIG. 4 is a partially disassembled perspective of the upper feed regulating member illustrating the elements by which the upper feed may be controlled; and

FIG. 5 is a partially cross sectioned and broken away perspective of a portion of the mechanism of this invention showing the coupling mechanisms by which the upper feed may be varied either together with or independent of any lower feed mechanism, and further showing apparatus through which the difference between the upper and lower feeds may be indicated.

DESCRIPTION OF THE PREFERRED EMBODIMENT posed work supporting surface 12 from one end of which rises a standard 14 supporting a bracket arm 16 overhanging the bed and terminating at its free end in a hollow head 18. Journaled lengthwise within the bracket arm, as shown in FIG. 2, is a main shaft 20 which drives all the moving parts of the sewing machine and which is rotated by means of a fly wheel 22 from any suitable source of power. Reciprocably mounted in bearings in the bracket arm head and reciprocated by suitable connections (not shown) to the main shaft, is a needle bar 24 carrying, at its lower end, a thread carrying needle 26 which cooperates with a suitable loop taker (not shown) mounted within the bed 10 below the surface 12 and driven through suitable connections to the main shaft in timed relationship with the needle to form stitches at a stiching point 28 in the throat plate 29. The disclosed machine also includes a conventional lower feed mechanism including a lower feed dog 30 preferably having two sets of teeth and which is adapted to be given lateral feed advance and return movement transverse to the major axis of the bracket arm, and vertical movement by conventional fourmotion means (not shown) driven from the main shaft 20. A conventional lower feed mechanism of this type is disclosed in US. patent to Van Ness No. 2,848,964 issued Aug. 26, 1958. Reciprocably mounted in the head 18 is a spring biased presser bar 32 carrying at its lower end a lit block 34 to which is adjustably secured a conventional presser foot 36 by means of a head screw 38.

Above the throat plate 29 overlaying the lower feed dog 30 is an upper feed dog 40 preferably having two sets of teeth adapted to cooperate with the lower feed dog to feed work material to and from the stitching point. The upper feed dog is firmly secured to a forked member 42 by means of screw 44 so as to move therewith. Pivotably secured by conventional means to the member 42 at opposite ends of each outer surface thereof are two pair of links 46 and 48. The links 46 are each further pivotably secured at their respective free end to one bifurcated leg 50 of a bellcrank 52 having a channel shaped leg 54 and a pair of bifurcated legs 50. The bifurcated legs 50- fit about side walls of the block 34 and are pivotally secured thereto by conventional means indicated as 51. Of course, the pivot point 51 may be on the frame of the machine instead of on the presser foot block, but with the present arrangement when the presser bar raised, the upper feed dog is raised along with the presser foot. Formed in the bellcrank end of block 34 is a milled slot within which a link 56 is positioned and pivotally mounted on the means pivotally securing the bellcrank 52 to the block 34. The other end of link 56 is fitted within the crotch of the forked member 42 and is pivotably mounted therein by the means pivotally securing the links 48 thereto. Each link 48 is further pivotally secured at its other end to one end of a rocker arm 58 which is secured at its other end by means of an integral C-clamp 60 to a rock shaft 62 journaled in a bushing 64 in the frame. It should be observed that the linkage comprising the bellcrank legs 50, the links 46 and 56 and the member 42 form a quadratic linkage (links 46 and 56 are the same length, as are legs 50 and 42) pivotable about 51 when the rocker arm 58 is given a rocking motion by the shaft 62 as will hereinafter be described. The upper feed dog is thus given a fed advance and return rocking movement by the motion of the arm 58. Vertical component of motion required to give the upper feed dog the necessary four motion action, as is known in the art, is supplied by means hereinafter described.

Secured to the free end of rock shaft 62 by an integral C-clarnp 66 is a second rocker arm 68 which is connected to and rocked by a toggle type feed regulating member generally indicated as 70, and which will be further described as this discussion proceeds. It should be noted that the rocker arms 58 and 68 and the rock shaft 62 act as a single rocker arm. The member 70 receives its input, as will be explained below, from one end of a pitman 72 whose other end comprises a sleeve or strap 74 surrounding an eccentric 76 which is secured to auxiliary shaft 72 journaled in the rear of the sewing machine head. Also secured to the shaft 78 is a grooved pulley 80 which meshes with a toothed timing belt 82 and thereby receives power from another grooved pulley 84 fast on the main shaft 20 and with which the belt 82 also meshes. Thus, the auxiliary shaft 78 is driven in timed relationship with the main shaft 20 and with the reciprocation of the needle bar 24.

Referring to FIGS. 3 and 4, the regulating member 70 will now be described. The member 70 comprises a carrier frame 86 of any suitable configuration, but here illustrated as including two substantially isosceles triangular end walls 88 and 89 spaced from one another at the side opposite the apex by a convex wall 90. Located adjacent the apex of each wall 88 and 89, on the exterior surface thereof, is a respective pin 92 and 93 secured to the respective wall at one end and journaled to turn in the frame at their free ends. The internal surface of each wall 88 and 89 includes a respective hole 94 and 95 within which is journaled a respective pin 96 and 97 each of whose other end is preferably press fitted into a hole in a respective link 98 and 99. Spaced from the respective pins 96 and 97 in each link 98 and 99 is a respective hole and 101 within which is poumaled a pin 102. The pin 102 is preferably press fitted within a hole (not shown) in the free end of pitman 72 and further passes through a pair of links 104 and 105 which are journaled to turn thereon. The links 104 and 105 are similar to links 98 and 99 and include respective holes 106 and 107 spaced from the center line of pin 102 by the same distance as the holes 100 and 101 are spaced from the center lines of the respective pins 96 and 97. Within each hole 106 and 107 is journaled a pin 108 which is preferably press fitted within a hole in the free end of rocker arm 68. It should be evident from the kinematics of the regulating member 70 that the oscillating motion of pitman 72 is transformed into a rocking motion at the rocker arm 68 when the center line of pin 108 is not coaxial with the center lines of pins 96 and 97, and that the further the center line of pin 108 is from the center lines of pins 96 and 97 the greater will be the rocking motion imparted to the arm 68, and through the mechanism described above,

the greater will be the feed advance and return motion imparted to the upper feed dog 40. The means for changing the spacing between the center of pin 108 and pins 96 and 97 will hereinafter be described. It should, however, be noted that only one of the two links 98 and 99, and only one of the links 104 and 105 are kinematically required.

In to provide the proper vertical displacement of the upper feed dog, so that the feed dog does not interfere with the work during the time that the needle is in the work, there is provided on the end of the shaft 78 a grooved pulley 110 which drives, by means of a meshing toothed timing belt 112, another grooved pulley 114 mounted on the end of a short stud shaft 116 journaled in the bottom of the machine head just above the feed dog 40. Secured to the shaft 116, in a position adjacent the leg 54 of the bellcrank 52, is an eccentric 118. A leaf spring 120, secured to the head 18 by a head screw 122, biases the leg 54 against the eccentric 118, and thus biases the bellcrank in a clockwise direction, as viewed in FIGS. 2. and 3. The spring 120 therefore acts to force the feed dog 40 downwardly against the work. A peg 124 aids the biasing power of the spring by pretensioning the same while the forked end 126 of the spring and the screw 122 allow for adjustment of the biasing pressure. It should be clear that during its return movement, the upper feed dog 40 is lifted by the rotating eccentric which pushes the leg 54 of the bellcrank clockwise in FIGS. 2 and 3 against the force of spring 120. Since the motions of the upper feed dog and the conventional lower feed dog 30 are derived from the rotation of the main shaft 20, they may operate together in a synchronous fashion by properly positioning the eccentrics 76 and 118.

To change the feeding rate of the upper feed dog 40 there are provided three control features: the first allows for simultaneously changing the upper and lower feeds; the second allows the upper feed to be changed relative of the lower feed; the third give the capability while sewing to change, for as long as desired, the upper feed relative to the lower feed, and then to return the upper feed to its previous setting. Each of these control features will now be described in order.

Journaled on a stud shaft 128 in the standard 14 is an indicator bracket 130 having a pointer 132 projecting toward the front of the standard. The bracket 130 is biased by a spring (not shown) against a regulating screw 134 threaded into the front of the standard and available for engagement by an operator. Pivotally mounted on the bracket 130 are a pair of levers 136 and 138. The lever 136 is connected to the mechanism (not shown) which regulates the feed of the lower feed dog 30, while lever 138 regulates the upper feed dog 40 as will be presently described.

J ournaled in the bracket arm 16 of the sewing machine is a hollow shaft 140 having a crank 142 secured to the standard end thereof. The lever 138 is mounted on a crankpin 143 of the crank 142 to thus angularly turn the shaft 140 when the screw 134 is rotated. As best illustrated in FIGS. 1 and 5, a crank 144 having an integral C-clamp is secured to the shaft 140 adjacent its other end. The crank 144 includes a bifurcated crank arm, between the tines of which is pivotally mounted a pin 146 having a threaded hole 147 transverse to the axis of the pin. A second hollow shaft 148, concentric with and passing through the hollow shaft 140, is further journaled within the bracket arm 16. The shaft 148 is longer than shaft 140 and has freely journaled thereon, at a location beyond the head end of shaft 140, a crank element 150 including two substantially parallel bushings 151 and 152 connected by an integral plate or link 153. The shaft 148 freely passes through bushing 151 while a pin 154 pass through bushing 152 and is pivotally secured to the plate 153. At the end opposite the plate 153 the pin 154 includes a threaded hole (not shown) transverse to its major axis. A regulating screw 156 having an operator engageable portion, whose adjustment purpose will hereinafter be described, is threadedly received within the hole 147 in pin 146 and within the hole in pin 154 thus effectively coupling the crank 150 to the shaft 140. Secured to the bushing 151 as by a press fit, so as to turn therewith, is a further crank 158 having a bore 159 formed in its crank arm 160. Fast on the shaft 148 as by an integral C-clamp is a shifting lever 162 including a slotted ear 163 and a crank arm 164. A pin 166 having a disk shaped head 167 extends through the slotted ear 163 with the head 167 abutting the bottom surface thereof. The pin 166 registers with and passes completely through the bore 159 so that a portion thereof projects above the arm 160. A coil spring 168 is fitted about the projecting portion of the pin and is secured in position by an abutting lock washer 169 or other such means at the projecting end of the pin. It should be clear that the crank arm 160, the shifting lever 162, the pin 1'66 and the spring 168 act as a clutch type of coupling unit to couple the shaft 148 to the crank element 150, and thus to the shaft 140. The crank arm 164 of the shifting lever 162 is bent at its free end and pivotally connected to one end of a lever 170 whose other end is pivotally connected to the exterior wall 89 of the feed regulator carrier frame 86 at a location remote from the pin 93. Movement of the lever 170 thus results in a pivoting of the feed regulator 70 about the journal pins 92 and 93 thereby changing the spacing of pins 96 and 97 relative to pin 108, and, as described above, this results in a change in feed advance and return motion of the upper feed dog.

Thus, to change the stitch length of both the top and bottom feeds, the operator thus merely turns the screw 134 so as to position the pointer 132 at the selected stitch length indicia (not shown) on the front of the standard 14. This causes a pivoting of the element 130 and the lovers 136 and 138. The lever 138 turns shaft 140, and through the mechanism described above, turns the regulator 70 through the proper angle to change the feed of the upper feed dog 40. Simultaneously, the lower feed dog 30 has its feed changed through the input of lever 136 to its conventional mechanism which includes the lever 136, the indicator 130 and the screw 134.

To change the upper feed independently of the lower feed, the regulating screw 156 is turned, thus resulting in a change in the angular relationship between crank 144 and crank 150. This, of course, changes the angular relationship between shaft 148 and shaft 140, i.e., shaft 148 is turned while shaft 140 remains in the position set by screw 134. Since shaft 148 is turned, the regulator 70 is pivoted and the upper feed only is varied; the lower feed is not effected since the lever 136 is not moved.

During certain sewing operations it may be desirable to effect a change in the upper feed relative to the lower feed while the machine is operating and to then return the feeds to their original conditions. One such operation would be during sewing with a balanced feed and a gathering of the upper material relative to the lower material is desired. The present mechanism allows for such an operation. Secured to the standard end of shaft 148 is a crank 172 to the arm of which is pinned the upper end of a rod 174, whose lower end is wrapped about a grooved pulley 176. The pulley is mounted on a stud shaft 178 which is secured to one end of a lever 180 and is pivotally mounted between its extremities on a shaft 182 secured to the sewing machine frame under the bed 10. The free end of the lever 18 is connected to one end of a chain 184 whose other end mounts a foot pedal (not shown).

To effect a difference in feeds, the foot pedal is depressed causing the lever 180 to pivot about shaft 182 and the shaft 148 to turn counterclockwise as seen in FIG. 3. This results in a disengagement of the shifting lever 162 from the crank 158 as the turning of shaft 148 overcomes the force of spring 168, so that the crank element 150 is not turned. This action moves the lever 170 and hence the regulator 70 and the upper feed dog without changing the angular relationship between bushing 151 and shaft 140. When the foot pedal is released a spring 186 returns the lever 180 to its normal position and hence the shaft 148 is returned to its predepression angle. The spring 168 returns the lever 162 to its original coupled position with crank 158.

The difference in feeds between the upper and lower feed dogs may be indicated by a pointer 188 on a graduated scale 190 on a bracket 191 mounted on the front of the standard 16. Fast on the shaft 140 is a mounting block 192 in which is secured a stud 194. A lever 196 is pivotably mounted on the stud 194 so as to turn relative thereto. The lever 196 includes a downwardly extending arm having a cam surface 198 formed therein and another arm in which is secured a pin 200. A cam follower pin 202 secured in the cross portion 153 of crank 150 is adapted to engage the cam surface 198 by the biasing action of a spring 204 mounted on the downwardly extending arm of the lever 196 acting against the crank 144. The pointer 188 is pivotally mounted intermediate its ends on a pin 206 secured to a mounting bracket 208 whose free end is secured to the bracket arm 16 of the sewing machine. The tail end of the pointer is forked shaped and is adapted to receive the pin 200 between its tines. When the regulating screw 156 is turned. a change in the angular relationship between the crank 144 and the crank element 150 occurs. Thus, the cam follower pin 202 moves in the cam surface 198 causing the lever 196 to turn on the stud 194, and the pin 200 engages the forked end of the pointer to pivot the pointer accordingly. When the basic stitch length is changed by screw 134 i.e., both the upper and lower feeds are changed, the crank element 150 and the mounting block 192 are moved synchronously, so that the follower pin 202 remains in t the same relative position on the surface of lever 196 and the pin 200 merely moves vertically in the forked end of the pointer, allowing the pointer to remain in the position previously determined by the screw 156. The scale 190 may he graduated from plus to minus wherein the plus indicates gathering of the upper material and the minus indicates stretching of the upper material relative to the lower material.

Although the present invention has been illustrated and described with respect to particular embodiments, eg. a machine having a lower feed dog rather than merely a surface against which the upper feed dog may operate, modifications thereof will occur to those skilled in the art. It is to be understood that this invention is not to be limited to the particular details disclosed, but that all modifications within the spirit and scope of the invention as defined by the appended claims are intended to be protected.

Having thus set forth the nature of the invention, what we claim herein is:

1. In a sewing machine comprising a frame including a bed having a work support, a standard rising from one end of the work support, a bracket arm at the top of the standard overhanging the work support and terminating in a sewing head, a drive shaft rotatably mounted lengthwise in said bracket arm, means for rotating said drive shaft, a needle mounted in said head for endwise reciprocation in timed relation to said drive shaft into and out of work engaging positions at a stitching point, a lower feed dog mounted in said bed below the work support for advancing work to said stitching point in timed relation to said needle reciprocation, and an upper feed dog mounted above said work support overlying said lower feed dog for cooperating with said lower feed dog to advance the work, wherein the improvement comprises: an auxiliary shaft rotatably mounted in said frame, a first flexible drive means operatively coupling said auxiliary shaft to said drive shaft for rotating said auxiliary shaft in a timed angular relation therewith, a pitman, means mounted on said auxiliary shaft for oscillating said pitman in timed relation to the rotation of said auxiliary shaft, a rocker arm, means operatively connecting said pitman to said rocker arm to impart a rocking motion to said arm, linkage operatively connecting said rocker arm to said upper feed dog for rocking the same to provide feed advance and return motion thereto in timed relation with said lower feed dog, a stud shaft rotatably mounted in said frame, eccentric means fast on said stud shaft, and a second flexible drive means operatively coupling said stud shaft to said auxiliary shaft for rotating said stud shaft in a time angular relation therewith, said eccentric means operatively engaging said linkage to impart a lifting and dropping motion to said upper feed dog in time relation to the reciprocation of said needle and its feed advance and return movements.

2. In a sewing machine as recited in claim 1 wherein said first flexible drive means comprises a pulley mounted on said drive shaft for rotation therewith, a first pulley mounted on said auxiliary shaft for rotation therewith, each of said pulleys having notches formed in the periphery thereof, and a continuous timing belt having teeth formed on the inner surface thereof and mounted about said drive shaft pulley and said first pulley with the teeth in meshing engagement with said notches, said second flexible drive means comprises a second pulley mounted on said auxiliary shaft for rotation therewith, a pulley mounted on said stud shaft for rotation therewith, each of said pulleys having notches formed in the periphery thereof, and a continuous timing belt having teeth formed on the inner surface thereof and mounted about said stud shaft pulley and said second pulley with the teeth in meshing engagement with said notches.

3. In a sewing machine as recited in claim 1 wherein said means operatively connecting said pitman to said rocker arm comprises an upper feed regulating member, said member comprising a carrier frame pivotally mounted in said sewing machine frame, first link means pivotably secured at one extremity to said pitman and at a second extremity to said rocker arm, second link means pivotably secured at one extremity to said pitman and at a second extremity to said rocker arm, second link means pivotably secured at one extremity to said pitman and at a second extremity to said carrier frame, and means for pivoting said carrier frame in said sewing machine frame to change the position of the second extremity of the second link means relative to the second extremity of the first link means, thereby changing the stroke of said rocker arm and said upper feed dog advance and return movements.

4. In a sewing machine as recited in claim :2 wherein said means for oscillating said pitman comprises an eccentric mounted on said auxiliary shaft for rotation therewith, said pitman including an eccentric strap surrounding the periphery of said eccentric to be oscillated thereby, said linkage connecting the upper feed dog to said rocker arm including a quadratic link mechanism, said upper feed dog being secured to a first of said links, said first link being pivotably secured to a second and to a third of said links, a bellcrank lever, each said second and third links being further pivotably secured to one arm of said bellcrank lever, the second arm of said lever being biased into engagement with said stud shaft eccentric.

5. In a sewing machine as recited in claim 4 including a presser bar mounted in said head for selective endwise translation, a block mounted on said presser bar, said bellcrank being pivotably mounted to said block at the juncture of said second link, said rocker arm being operably connected to said first and second links at the juncture thereof so as to rock said linkage about said bellcrank pivot.

'6. In a sewing machine as recited in claim 5 wherein said means operatively connecting said pitman to said rocker arm comprises an upper feed regulating member, said member comprising a carrier frame pivotably mounted in said sewing machine frame, first link means pivotably secured at one extremity to said pitman and at a second extremity to said rocker arm, second link means pivotably secured at one extremity to said pitman and at a second extremity to said carrier frame, and means for pivoting said carrier frame in said sewing machine frame to change the position of the second extremity of the second link means relative to the second extremity of the first link means, thereby changing the stroke of said rocker arm and said upper feed dog advance and return movements.

7. In a serm'ng machine as recited in claim 3 wherein said means for pivoting said carrier frame comprises a first shaft journaled in said bracket arm, a shifting lever fast on said shaft, means operatively connecting said shifting lever to said carrier frame for pivoting the same in said sewing machine frame when said shaft is turned, and means for turning said shaft.

8. In a sewing machine as recited in claim 7 wherein said means turning said shaft comprises a crank secured to said shaft, a rod operably connected at one end to said crank, a lever pivotably connected to the sewing machine frame intermediate its extremities, the other end of said rod being operably connected to one extremity of said lever, and operator engageable means connected to a second extremity of said lever for selectively pivoting said lever to thereby turn said shaft.

9. In a sewing machine as recited in claim 7 wherein said means for turning said first shaft comprises a second shaft journaled in said bracket arm, said second shaft being concentric with and overlaying said first shaft, means coupling said second shaft to said shifting lever to move the same when said first shaft is turned, a crank mounted on said second shaft, a bracket pivotably mounted in said frame, a lever operably connected to said crank and to said bracket to turn said second shaft when said bracket is pivoted, a second lever operably connected to said bracket and adapted to operably engage said lower feed dog, and an operator influenced regulating screw mounted in said frame in a location adjacent "said bracket, said bracket being biased to engage the end of said screw such that rotation of said screw pivots said bracket, thereby simultaneously regulating the upper and lower feed dogs.

10. In a sewing machine as recited in claim 9 wherein said means coupling said second shaft to said shifting lever comprises a crank secured to said second shaft, a crank element including a bushing journaled on said first shaft, a second regulating screw mounted on said crank and threadedly received in said crank element at a location radially removed from said shafts to couple said crank to said crank element, a crank arm fast on said bushing, and means. coupling said crank arm to said shifting lever, whereby said first shaft may be turned by rotation of said first or said second regulating screw, rotation of said second regulating screw regulating the upper feed dog independently of said lower feed dog.

11. In a sewing machine as recited in claim 10 wherein said means coupling said crank arm to said shifting lever comprises a resilient coupling including a pin extending axially through an aperture in a portion of said arm and through an aperture in a portion of said lever, said pin having means on one end thereof for preventing said pin from fully passing through said apertures, said pin having an axial dimension greater than the combined thickness of said portions such that part of said pin projects out from said portions when said one end is flush with one of said portions, a spring coiled about said projecting part of said pin, and means on the other end of said pin abutting said spring for securing said spring to said pin.

12. In a sewing machine as recited in claim 11 including a crank secured to said first shaft, a rod operably connected at one end to said crank, a lever pivotably connected to the sewing machine frame intermediate its extremities, the other end of said rod being operably connected to one extremity of said lever, and operator engageable means connected to the second extremity of said lever for pivoting said lever to thereby turn said first shaft, whereby said shifting lever decouples from said crank arm and said carrier frame may be selectively pivoted without effecting the position of said first and second regular screws.

13. In a sewing machine comprising a frame including a bed having a Work support, a standard rising from one end of the work support, a bracket arm at the top of the standard overhanging the work support and terminating in a sewing head, a drive shaft rotatably mounted lengthwise in said bracket arm, means for rotating said drive shaft, a needle mounted in said head for endwise reciprocation in timed relation to said drive shaft into and out of work engaging positions at a stitching point, and an upper feed dog mounted above said work support for advancing work to said stitching point, wherein the improvement comprises: an auxiliary shaft rotatably mounted in said frame, a first flexible drive means operatively coupling said auxiliary shaft to said drive shaft for rotating said auxiliary shaft in a timed angular relation therewith, a pitman, means mounted on said auxiliary shaft for oscillating said pitman in timed relation to the rotation of said auxiliary shaft, a rocker arm, means operatively connecting said pitman to said rocker arm to impart a rocking motion to said arm, linkage operatively connecting said rocker arm to said upper feed dog for rocking the same to provide feed advance and return motion thereto in timed relation with said needle reciprocation, a stud shaft rotatably mounted in said frame, eccentric means fast on said stud shaft, and a second flexible drive means operatively coupling said stud shaft to said auxiliary shaft for rotating said stud shaft in a timed angular relation therewith, said eccentric means operatively engaging said linkage to impart a lifting and dropping motion to said upper feed dog in timed relation to the reciprocation of said needle and its feed advance and return movements.

14. In a sewing machine as recited in claim 13 wherein said first flexible drive means comprises a pulley mounted on said drive shaft for rotation therewith, a first pulley mounted on said auxiliary shaft for rotation therewith, each of said pulleys having notches formed in the periphery thereof, and a continuous timing belt having teeth formed on the inner surface thereof and mounted about said drive shaft pulley and said first pulley with the teeth in meshing engagement with said notches, said second flexible drive means comprises a second pulley mounted on said auxiliary shaft for rotation therewith, a pulley mounted on said stud shaft for rotation therewith, each of said pulleys having notches formed in the periphery thereof, and a continuous timing belt having teeth formed on the inner surface thereof and mounted about said stud shaft pulley and said second pulley with the teeth in meshing engagement with said notches.

15. In a sewing machine as recited in claim 13 wherein said means operatively connecting said pitman to said 11 rocker arm comprises an upper feed regulating member, said member comprising a carrier frame pivotally mounted in said sewing machine frame, first link means pivotally secured at one extremity to said pitman and at a second extremity to said rocker arm, second link means pivotably secured at one extremity to said pitman and at a second extremity to said carrier frame, and means for pivoting said carrier frame in said sewing machine frame to change the position of the second extremity of the second link means relative to the second extremity of the first link means, thereby changing the stroke of said rocker arm and said upper feed dog advance and return movements.

16. In a sewing machine as recited in claim 14 wherein said means for oscillating said pitman comprises an eccentric mounted on said auxiliary shaft for rotation therewith, said pitman including an eccentric strap surrounding the periphery of said eccentric to be oscillated thereby, said linkage connecting the upper feed dog to said rocker arm including a quadratic link mechanism, said upper feed dog being secured to a first of said links, said first link being pivotably secured to a second and to a third of said links, a bellcrank lever, each said second and third links being further pivotably secured to one arm of said bellcrank lever, the second arm of said iever being biased into engagement with said stud shaft eccentric.

17. In a sewing machine as recited in claim 16 including a presser bar mounted in said head for selective endwise translation, a block mounted on said presser bar, said bellcrank being pivotably mounted to said block at the juncture of said second link, said rocker arm being operably connected to said first and second links at the juncture thereof so as to rock said linkage about said bellcrank pivot.

18. In a sewing machine as recited in claim 17 wherein said means operatively connecting said pitman to said rocker arm comprises an upper feed regulating member, said member comprising a carrier frame pivotably mounted in said sewing machine frame, first link means pivotally secured at one extremity to said pitman and at a second extremity to said rocker arm, second link means pivotably secured at one extremity to said pitman and at a second extremity to said carrier frame, and means for pivoting said carrier frame in said sewing machine frame to change the position of the second extremity of the second link means relative to the second extremity of the first link means, thereby changing the stroke of said rocker arm and said upper feed dog advance and return movements.

19. In a sewing machine as recited in claim 15 wherein said means for pivoting said carrier frame comprises a first shaft journaled in said bracket arm, a shifting lever fast on said shaft, means operatively connecting said shifting lever to said carrier frame for pivoting the same in said sewing machine frame when said shaft is turned, and means for turning said shaft.

References Cited UNITED STATES PATENTS 3,099,974 8/1963 Chudner 1l2207 3,162,158 12/1964 Chudner 112-207 3,262,410 7/1966 Cherries 112-212 3,540,391 11/1970 Haye l12212 RICHARD J. SCANLAN, 1a., Primary Examiner jgggg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 605, 662 Dated September 20, 1971 Inventor-(S) Erich M. Willenbacher, Karl-Heinz Michel and Werner J. Mayer It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 20 before "shaft" insert arm --7 Column 4, line 38 after "dog" insert 4O Column 4, line 53 "72" should read 78 Golumn 5, line 1 "pournaled" should read journaled Column 8, line 59 delete "second link means Column 8, line 60 delete "pivotably secured at one extremity to said pitman and"; Column 8, line 61 delete "at a second extremity to said rocker arm,

Signed and sealed this 21st day of March 1972.

QSEAL} Attest:

ELDMZiRD MQFLETCHERJR. ROBERT GOTTSCHALK attesting Officer Commissioner of Patents 

